Synthesis and Polymerization of a Four-Arm Star with Pendent Cyclopentadienyliron Moieties

Sandwich complex-containing macromolecules: property tunability through versatile synthesis

Sandwich complexes feature unique properties as the physical and electronic properties of a hydrocarbon ligand or its derivative are integrated into the physical, electronic, magnetic, and optical properties of a metal. Incorporation of these complexes into macromolecules results in intriguing physical, electrical, and optical properties that were hitherto unknown in organic-based macromolecules. These properties are tunable through well-designed synthetic strategies. This review surveys many of the synthetic approaches that have resulted in tuning the properties of sandwich complex-containing macromolecules. While the past two decades have seen an ever-growing number of research publications in this field, gaps remain to be filled. Thus, we expect this review to stimulate research interest towards bridging these gaps, which include the insolubility of some of these macromolecules as well as expanding the scope of the sandwich complexes.

UV spectroscopic studies and charge transfer properties of azobenzene-containing cyclopentadienyliron complexes of arenes: a combined experimental and density functional theoretical study

This study investigates the UV-Vis absorption and fluorescence emission of newly synthesized (η(6)-4-(4-nitrophenylazo) phenoxyl benzene) (η(5)-cyclopentadienyl) iron hexafluorophosphate (Fc-azo). Quantum chemical calculations of the orbital energy, geometrical structure, absorption spectra, and first hyperpolarizability (β) values of the Fc-azo were carried out using density functional (DFT/B3LYP and TD-DFT) methods. Comparisons between hydroxyl azobenzene compound and Fc-azo were made. Results showed that the observed spectra were in good agreement with the calculated values. The positive solvatochromism of the UV-Vis absorption of Fc-azo upon the increase in solvent polarity from the experiment and the calculated HOMO and LUMO energies showed that charge transfer occurred within the molecule. Moreover, the change in electron distribution led to the improved β for Fc-azo.